The invention relates to a communication system for a vehicle and to a method for operating such a communication system. Motor vehicles nowadays are equipped in many cases with a communication system via which a mobile radio connection to a mobile radio network can be effected from the interior of the vehicle. In this case, the communication system can include a hands-free installation which can be connected temporarily during the journey to a mobile terminal such as a smart phone, for example. In this case, the connection can be effected in a wired manner or else by means of a wireless local radio connection, for example in accordance with the Bluetooth standard.
Furthermore, provision can be made for the communication system of the vehicle to include a mobile radio unit fixedly integrated in the vehicle, e.g. a so-called telematics unit. Such a unit can be used to set up a connection to central switching stations of a mobile radio network and, in particular, a telephone connection to central service providers for further control units of the vehicle such as, for example, for a navigation device or for a multimedia device. In this respect, BMW Group offers the System Connected Drive, for example, via which a connection to an information service, the so-called concierge service, or to an emergency call center can be set up directly from a vehicle.
In addition, a telematics unit can be used to set up a data connection to central computers such as, for example, so-called “backend servers” of national information services or to database services. Such connections can include Internet connections, in particular.
Components of a communication system, which can be used to establish a wireless connection to a computer network, for example wireless local area network (WLAN) components, can furthermore be provided in a vehicle.
For the respective connections into the mobile radio or computer networks, corresponding antennas are provided in the vehicle, in particular in the interior and/or on the exterior of the vehicle. Via these antennas communication units situated fixedly or temporarily in the interior of the vehicle can be connected to radio units and/or network components situated outside the vehicle. By way of example, one or a plurality of mobile radio antennas can be pro vided on the exterior of the vehicle in order to set up a wireless connection to base stations of mobile radio networks. By way of example, a WLAN antenna can be provided in the interior of the vehicle. The interior and exterior antennas can be connected to one another for example via a controller fitted in or on the vehicle.
EP 1 863 119 A1, EP 1 903 632 A1 and DE 10 2010 061 995 A disclose antenna modules for mobile radio connections for vehicles which, in each case, include a plurality of antennas. The contents of the publications cited above are hereby incorporated by reference in the present description.
It is an object of the invention, with a communication system for a vehicle which includes a plurality of antennas, to enable a connection between communication units which is as stable as possible.
This and other objects are achieved according to the invention by a communication system for a vehicle including a plurality of antennas and a plurality of transmitting and/or receiving interfaces. At least one first antenna is arranged in the interior of the vehicle. At least one second antenna is arranged on the exterior of the vehicle. The first antenna is designed to wirelessly establish via a first transmitting and/or receiving interface at least one part of a data connection between a first communication unit situated in the interior of the vehicle and at least one first network base unit situated outside the vehicle. The second antenna, is designed to wirelessly establish via a second transmitting and/or receiving interface at least one part of a data connection between a second communication unit situated in the interior of the vehicle and the first and/or a second network base unit situated outside the vehicle. The communication system is designed in such a way that a data connection can be established within the vehicle between the second communication unit and the first antenna via the second transmitting and/or receiving interface.
By virtue of the fact that a data connection can be established within the vehicle between the second communication unit and the first antenna via the second transmitting and/or receiving interface, particularly in the case of a failure of the second antenna, it can be ensured that a mobile radio and/or data connection to a network base unit and thus to the mobile radio and/or data network or to the outside world can still be established by a communication unit situated in the interior of the vehicle. This advantage of the invention is extremely important for example if the second antenna fails owing to an accident of the vehicle and an emergency call is intended to be transmitted from the interior of the vehicle.
The invention is based on the insight, in particular, that the first antenna, arranged within the vehicle, in the case of an accident of the vehicle, is protected against damage significantly better than the second antenna, situated outside the vehicle. In this case, the invention is furthermore based on the insight that the interior of the vehicle affords good protection against mechanical damage for the first antenna. In this case, the term interior encompasses, in particular, a space which with high probability remains relatively intact in the case of an accident or a space which is insensitive to externally acting mechanical impacts and/or is protected by means of one or more protection devices, such as e.g. the passenger compartment, the trunk and/or the engine compartment. The second antenna, arranged on the exterior of the vehicle is fitted in particular at least partly outside the vehicle body, for example in a housing fitted to the exterior of the vehicle roof, such as e.g. a so-called roof fin. In this case, this mounting location is particularly suitable for bringing about on the vehicle side with the second antenna a higher reception sensitivity and/or effective emission power in comparison with the vehicle-internal first antenna, particularly because there are hardly any shielding effects of the vehicle body there.
What can furthermore advantageously be achieved by means of the invention is that the communication system comprises within the vehicle only a first antenna, which, however, is designed for optionally implementing two communication connections, in particular for a first network connection to a mobile terminal within the vehicle, which may be a WLAN connection, and for a second network connection from a mobile radio unit provided fixedly in the vehicle, in particular from a telematics unit, directly to a network base station situated outside the vehicle. In the context of the present invention, the term WLAN should be understood as a generic term for various radio transmission technologies by way of which computers can be networked, for example in accordance with one of the technology standards IEEE 802.11xx.
A communication connection brought about by the communication system can be designed as a voice and/or data connection, e.g. according to one of the technology standards GSM (Global System for Mobile Communications) or LTE (Long Term Evolution). The at least one antenna provided within the vehicle can be designed as a WLAN antenna in order, as an antenna of the WLAN access point, to establish a wireless connection to a mobile terminal situated in the vehicle. For this purpose, corresponding components and interfaces for processing data and signals corresponding to the respective technology standards are provided in the vehicle. In this case, components and/or interfaces can also be provided which transmit signals and/or data between the vehicle-internal WLAN access point and mobile radio base stations situated outside the vehicle and/or process said signals and/or data.
The transmitting and/or receiving interfaces can include, in particular, components which can process signals and/or data according to at least one of the standards WLAN and LTE. The transmitting and/or receiving interfaces can be designed, in particular, at least partly as corresponding integrated circuits (chip). The communication units can be designed in each case for establishing mobile radio connections and/or data transmission connections. They can be temporarily situated in the vehicle as mobile units (e.g. as a smartphone) or fixedly installed in the vehicle (e.g. as a telematics unit).
The invention makes it possible, in particular, for the vehicle antenna used for the respective communication device to be flexibly coupled to the communication device as required. The connection between the second communication unit and the first antenna can be established automatically in this case when predefined conditions occur. The conditions can be detected by use of a sensor system. For this purpose, it is furthermore possible to predefine coupling rules with which the coupling is effected in a parameter-controlled and/or sensor-controlled manner. The predefined conditions can encompass a failure and, in particular, the entire or partial mechanical and/or electrical destruction of the second antenna and/or an accident of the vehicle. A corresponding coupling rule can be, for example, the fact that in the case of an accident event which is detected by a sensor unit of the vehicle and which triggers an airbag, for example, firstly a check is made to ascertain whether a communication connection to a network base station can be effected via at least one antenna fitted to the exterior of the vehicle and, otherwise, a communication connection is set up via at least one antenna, arranged in the vehicle. A corresponding check can also be initiated in a different way, for example if an emergency call button is pressed in the vehicle.
In the communication system, in particular a switching arrangement can be provided, by which optionally a data connection to the first antenna or to the second antenna can be established by the second transmitting and/or receiving interface. By means of the switching arrangement, in particular the first transmitting and/or receiving interface can also be switchable or switched between the two antennas. The switching arrangement can include, in particular, a wired double pole double throw (DPDT) switch and/or control components which are used to implement the coupling rules.
The transmitting/receiving unit provided for the interior can thus be switched to the exterior as necessary. This may be beneficial e.g. for dialing into an external WLAN hotspot.
In one preferred exemplary embodiment of the invention, the first and, in particular, also the second transmitting and/or receiving interface and the first antenna are arranged in the interior of the vehicle in a transmitting/receiving unit. This unit can include a so-called network access device (NAD).
By means of the invention, a stable communication connection and a good connection quality toward the outside can be made possible even for a plurality of devices situated in the interior region of the vehicle.
In accordance with a further advantageous exemplary embodiment of the invention, on the exterior of the vehicle, a third antenna is arranged and, in the interior of the vehicle, a third transmitting and/or receiving interface is arranged, which can be used to establish at least one part of a communication connection between the first, the second and/or a third communication unit arranged in the vehicle and the network base unit situated outside the vehicle. At least one of the transmitting and/or receiving interfaces can be, in particular, an LTE interface. In particular, the first transmitting and/or receiving interface can be a WLAN interface comprising at least one WLAN-enabled component. The second and/or the third transmitting and/or receiving interface can be, in each case, a mobile radio interface, in particular an LTE interface, which comprises at least one LTE-enabled component. The first antenna, can be designed in particular in such a way that it can transmit and/or receive both WLAN signals and mobile radio signals, in particular LTE signals.
In a further advantageous exemplary embodiment of the invention, the second and third antennas are arranged, in each case, on the roof of the vehicle. They are surrounded in particular by a common enclosure, designed for example as a roof fin.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.